Disease Information for Niemann-Pick disease: Definition

  • A group of diseases marked by autosomal recessive inheritance and accumulation of sphingomyelin in cells of the RETICULOENDOTHELIAL SYSTEM; They are divided into 5 subtypes: A-E; Type A (classic infantile form) is caused by a deficiency of SPHINGOMYELIN PHOSPHODIESTERASE and presents at age 6-12 months with progressive hepatosplenomegaly and neurologic deterioration; Type B (non-neuronopathic form) presents in childhood with hepatosplenomegaly and pulmonary infiltrates; Type C (chronic neuronopathic form) is caused by defective intracellular cholesterol transport and is divided into severe infantile, late infantile, juvenile, and neonatal hepatitis forms; Type D (Nova Scotian Variant) is phenotypically similar to type C; Type E is an adult non-neuronopathic form; Nieman Pick disease Type F (sea-blue histiocyte disease); Niemann-Pick disease (NPD) is a group of rare inherited disorders of fat metabolism; At least five types of Niemann-Pick disease have been identified

    (NPD types A, B, C, D, and E); Symptoms of types A and B occur as a result of a deficiency of the enzyme acid sphingomyelinase (ASM), which is needed to break down sphingomyelin, a fatty substance found mostly in the brain and nervous system; This deficiency results in abnormal accumulation of excessive amounts of sphingomyelin in many organs of the body such as the liver, spleen, and brain; Symptoms of type C occur because of impaired trafficking of large molecules within cells, which results in the

    accumulation of excessive amounts of cholesterol and other lipids (glycosphingolipids) tissues throughout the body; The metabolic defect in type C can lead to a secondary reduction in ASM activity in some cells; The division of Niemann Pick disease into groups A, B, C and D was proposed

    by Allan Crocker in 1961 after he and Sidney Farber had expanded the category of Niemann-Pick disease by applying the diagnosis to all patients with "foam cells" and lipid storage in the tissues; This had led to the inclusion of older and less severely affected people than those originally described by Niemann and Pick; Symptoms common to all types of Niemann-Pick disease include yellow

    discoloration of the skin, eyes, and/or mucous membranes (jaundice), progressive loss of motor skills, feeding difficulties, learning disabilities, and an abnormally enlarged liver and/or spleen (hepatosplenomegaly); The different types of Niemann-Pick disease are inherited as autosomal recessive traits; [NORD]